Which of the following can you physically change for a pure substance such as water, without altering the chemical composition?

Biuret reagent will indicate the presence of

weeeeeb [17]

Biuret reagent will indicate the presence of protein in a given sample. It is also known as the Piotrowski's test. This reagent consists of copper (II) sulfate and sodium hydroxide. It detects peptide bonds by the reaction of the copper ions in an alkaline solution. The copper ions would form violet colored complexes when peptide is present in the solution. From this test, concentration can be calculated since the intensity of the color depends on the amount of peptide bonds and according to the Beer-Lambert law concentration and the absorption of light is proportional. The concentration is calculated by a spectrophotometric technique at a wavelength of 540 nm.

5 0

3 years ago

When an ionic compound dissolves in water, the individual ions first leave the crystal lattice and then each ion becomes surroun

vichka [17]

The entropy of the process in which the individual ions first leave the crystal lattice is positive while the entropy of the process whereby the each ion becomes surrounded by a cluster of polar water molecules is negative.

<h3>What is entropy?</h3>

The term entropy has to do with the degree of disorder in a system. The higher the entropy of the system, the more the disorderliness of the system.

Now, the entropy of the process in which the individual ions first leave the crystal lattice is positive while the entropy of the process whereby the each ion becomes surrounded by a cluster of polar water molecules is negative.

Learn more about entropy: brainly.com/question/13146879

3 0

1 year ago

am gonna cry plz answer Which is not an inter molecular force? Select one: a. Inter atomic bonds b. van der waals forces c. hydr

tatyana61 [14]

Answer:

inter atomic bonds

Explanation:

because it is loosely held

5 0

3 years ago

What is the molarity of a solution in which 7.1 g of sodium sulfate is dissolved in enough water to make 100. mL of solution?

Sidana [21]

Answer:

0.50 M

Explanation:

Given data

Mass of sodium sulfate (solute): 7.1 g

Volume of solution: 100 mL

Step 1: Calculate the moles of the solute

The molar mass of sodium sulfate is 142.04 g/mol. The moles corresponding to 7.1 grams of sodium sulfate are:

$7.1g \times \frac{1mol}{142.02g} = 0.050mol$

Step 2: Convert the volume of solution to liters

We will use the relation 1 L = 1000 mL.

$100mL \times \frac{1L}{1000mL} =0.100L$

Step 3: Calculate the molarity of the solution

$M = \frac{moles\ of\ solute }{liters\ of\ solution} = \frac{0.050mol}{0.100L} =0.50 M$

3 0

2 years ago

Read 2 more answers

Empirical formula of a compound composed of 32.1 g potassium (k) and 6.57 g oxygen (o)?

tester [92]

The empirical formula is K₂O.

The empirical formula is the simplest whole-number ratio of atoms in a compound.

The ratio of atoms is the same as the ratio of moles.

So, our job is to calculate the molar ratio of K to O.

Step 1. Calculate the moles of each element

Moles of K = 32.1 g K × (1 mol K/(39.10 g K =) = 0.8210 mol K

Moles of O = 6.57 g O × (1 mol O/16.00 g O) = 0.4106 mol 0

Step 2. Calculate the molar ratio of each element

Divide each number by the smallest number of moles and round off to an integer

K:O = 0.8210:0.4106 = 1.999:1 ≈ 2:1

Step 3: Write the empirical formula

EF = K₂O

5 0

3 years ago